It is crucially important for prevention or treatment of various oral diseases to know the condition of the oral cavity, that is, the risk for oral disease and the status of oral hygiene. Hence, development of methods for determining the risk for oral disease and the status of oral hygiene is strongly demanded. The risk for oral disease refers to, for example, the dental caries risk, that is how likely the oral cavity is to be affected by dental caries, the periodontal disease risk, that is, how likely the oral cavity is to be affected by periodontal diseases, and the like. Conventionally, diagnosis of the risk for oral disease and the status of oral hygiene has been carried out by a doctor or the like based on measurement results obtained by measuring individual component or property that reflects the risk for oral disease or the status of oral hygiene using saliva or gargle liquid collected from a subject as a sample.
For example, the mutans bacteria count in saliva, the acid buffering ability of saliva, or the like is known to reflect the dental caries risk. Either when the mutans bacteria count is high or when the acid buffering ability is low, the dental caries risk is considered to be high. Here, as methods for detecting mutans bacteria, a detection method using an antibody (Patent Document 1), a detection method using resazurin which is an oxidation-reduction indicator (Non-patent Document 1), and the like have been already known.
Further, for example, occult blood, leukocyte, alkaline phosphatase, or the like is known to reflect the periodontal disease risk. That is, when the periodontal disease is accompanied by destruction of gum tissues, the occult blood is detected in saliva and leukocytes gather to an area affected by the periodontal disease. Further, a large amount of alkaline phosphatase is produced by bacteria related to the periodontal disease. Here, as a method for detecting the occult blood, for example, a hemoglobin contact activation method is known (Patent Document 2). Also, as a method for detecting the leukocytes, a detection method utilizing esterase activity or protease activity of leukocytes is known (Patent Document 3).
Examples of examination systems for the disease of the oral cavity that have been in practical use will be described below.
As an examination system related to bacteria causing the periodontal disease, known is a system capable of evaluating the degree of infection and the type of infection for bacteria causing the periodontal disease, wherein blood is collected at home and mailed in a specialized container to measure the level of plasma antibodies against four types of the bacteria causing the periodontal disease. However, this system is only able to carry out the examination for the bacteria causing the periodontal disease and requires six business days for the result to become available.
Further as an examination system related to the periodontal disease, known is a system capable of determining incidence of the periodontal disease by detecting the occult blood in saliva. According to this system, the examination can be carried out in as short as 5 minutes but items other than the occult blood cannot be examined.
Further, as examination system related to the dental caries and periodontal disease, known is a system for detecting mutans bacteria and bacteria causing the periodontal disease by a PCR method using saliva collected in a dental clinic as a sample. According to this system, two items of the count of mutans bacteria and the count of the bacteria causing the periodontal disease can be simultaneously examined but six business days are required for the result to become available.
Further, as a system for detecting mutans bacteria, known is a system capable of detecting mutans bacteria by measuring a reaction of reducing resazurin by mutans bacteria. However, this system is able to carry out only the measurement of mutans bacteria, requires temperature adjustment to 37° C., and takes as long as 15 minutes.
Further, as the system for detecting mutans bacteria, besides the above, known is a system for determining the mutans bacteria count on the basis of the density of colonies that were formed by culturing mutans bacteria in saliva in a selection medium (Non-patent Document 2). However, this system is able to carry out only the measurement of mutans bacteria, requires temperature adjustment to 37° C., and takes as long as 48 hours.